Hi AllJust bought a 1972 TR6 650, any reason why I can't use Valvoline VR1 20w50 racing oil as engine oil? The oil should be shared between the crankcase and the primary chaincase, I know there is oil in the primary chaincase because it's leaking! Also some clutch slip, just like the last one I bought...

ANY oil with "friction modifiers" in it will cause clutch-slip in Triumphs made from 1970-on, where oil is shared between the engine and primary chain case.

The chain case is being used as a big plenum chamber to vent the engine. This was not a problem when these bikes were first produced, but with the popularity of overhead cam auto engines and a desire for better fuel mileage, these additives were introduced, thus causing OUR problems with using this oil.

There are several alternative oils that do not have these friction modifiers. Honda and Yamaha dealers stock their own brands, and there are others.

By the way: Why are you using 20W50 instead of straight-weight 40, as Triumph recommended?These are air-cooled engines, and the heat from the crankcase is carried away by the oil, and is disbursed by the walls of the oil tank or, in your case, by the oil reservoir of the frame.

Use 20w/50 Valvoline 4 stroke motorcycle oil. It doesn't have the friction modifiers that affect the clutch and is designed for air cooled engines. Triumph may have recommended the single weights at one time and expected you to change them winter and summer but when the multi-weights became available they switched the recommendation to those. As long as you change on a regular basis the 20w/50 motorcycle specific oils work fine. Better circulation on cold start up and protection at high temps.

Also, the o.p.'s "Loc:" is "UK"; although it's a beautiful sunny morning, even if he's in the south, the temperature was in single figures early on; if he fancied an early-morning ride, "straight-weight 40" wouldn't do the bike's big-ends and top end any favours whatsoever.

Does your bike have shared oil in the engine and primary? If so, thee might be an issue with clutch slipping. It's difficult to determine which bike will have clutch slip and which won't. I have a friend with a '71 using VR-1 with no clutch slipping reported.

I use it in all my bikes, but the issue is oil availability vs price for me. I can get motorcycle oils at the Harley shop for big bucks, or VR-1 at the auto parts store for a bit less, so that's what I use.

If you try it and the clutch slips, then maybe it's time for a clutch strip and clean. We have to do it every once in a while anyway...

I run the Quicksilver syn 20w50 mc oil that is sold by WalMart. It's made just for motorcycles and has the appropriate Zn etc. in it plus lacks the bad juju for clutches. Has worked fine on all my bike, including brits, for years now. A little more than the Valvoline MC oils but it is synthetic and I like to give the old bikes every little bit of help I can.

If you look at Valvoline's website and product specs...Their 20-50 motorcycle oil has what many consider to be less ZDDP than desirable for older engines, less than 1100 PPM. The ZR1 is with range with 1400 PPM... But if it works for you then it's just fine...

That test is at least nine years old. Automotive oils have changed in nine years and probably bike oil? It appears the tests were done in a lab and not after many miles of actual road or race riding? Oil testing using methods like pressing steel balls into spinning wheels has come under a lot of criticism lately because they don't reflect the dynamics of what goes on in a running engine.

Thanks every one. I have a non shared oil model, primary clutch and engine. I should be fine with VR1 20/50. Since my cars are older and I have to use redline ZDDP additive. I will use some redline ZDDP additive to my VR1 oil just to be safe and get above 1400ppm.

Thanks for all the detailed replies. I can only find one seller of Valvoline 20w50 motorcycle oil in the UK (on Amazon) at GBP12.50 a litre. Lucas 20W50 motorcycle oil is a possibility, or buy some Motul 3000 and use a ZDDP additive.

Thanks for all the detailed replies. I can only find one seller of Valvoline 20w50 motorcycle oil in the UK (on Amazon) at GBP12.50 a litre. Lucas 20W50 motorcycle oil is a possibility, or buy some Motul 3000 and use a ZDDP additive.

There are any number of suitable 20/50 motorcycle oils in GB - syn., semi- and straight dead dino juice - look for one marked "4T" and/or "V-twin".

You do not need to faff around with "ZDDP additive", any one that meets API SG spec. or earlier will have sufficient ZDDP.

There's much twaddle posted on Britbike forums about ZDDP; I would strongly advise that you 'phone Fuchs Lubricants (think Silkolene) at Belper, Derbyshire, who r&d and blend in GB. Ime, you'll speak to someone who actually knows what they're talking about (as opposed to a 'Customer Service Representative' reading answers off a computer screen, or someone reposting an amalgam of half-remembered information read weeks and months ago on the aforementioned forums ... ).

As your bike uses the same oil in engine and primary transmission, any oil you select should also meet JASO MA2 spec. - essentially, means it's missing the additives that can cause clutch slip.

When the Speed Twin cam out in 1938 ZDDP was an experimental additive being tested as a corrosion inhibitor. When the 650 came out in 1950 ZDDP was not found in many motor oils in the USA. The late 50'sand 60's HP increases in OHV V-8's using hotter cams with more spring pressure was one of the reasons for increased ZDDP.. I would think the Triumph radius tappet and about 180 pound open spring pressure is a lot less stressful than the punk kid down the street with a built Chevy engine having 300 plus pounds open pressure on a .840 diameter partial contact tappet.

Triumph has a well known problem with rapid cam wear on the earlier machines. As a matter of practice, I always fit nitrided cams to any engine I build in order to slow down this problem.

Inlet cams have a much easier life. Nitrided inlet cams with breather drillings are rather rare on the used cam market. So in order to help the situation, I add oil with ZDDP or additives when I can.

Despite the light loadings of these components, rapid cam wear is a real issue. Anyone with a 69 or later bike need not worry too much about it.

I imagine that there are clutches that are designed to run in the modern oils. It seems to me an opportunity for some enterprising individual or concern to manufacture clutch plates that work with the modern oils.

So, with nitrided cams and new clutch pack, a Triumph owner could select whatever oil it pleased him, including that Royal Purple or Lucas oil that seem not to live up to their claims on the above oil testing.

Or you could even use Slick 50 which claims were proven over stated, to be kind. The only thing slick about it was the advertising.